The tricky part about getting those Cottonwood Pass (or other similar trail heads) via Recreation.gov is that they are VERY popular and seem even more so this year. I'm sure that is likely due to pent up demand from so many who had to cancel plans last summer. Regardless, each day new permits are coming online for six months out, but in my experience monitoring, they are mostly gone within 2-3 minutes for popular trail heads that provide a relatively easy access to Whitney from the West. If you get online at the right time each morning and start refreshing as the moment arrives, you have a decent chance. Otherwise, you try again the next day or hope for something when it is time to release the "walk up" portion of the permit inventory.
Good luck!
